Plant for pneumatic, hydraulic, or like fluid control



, J. IMERCIER Feb. 3, 1942.

PLANT FOR PNEUMATIC, HYDRAULIC, 0R LIKE FLUID CONTROL 2 Sheets-Shed 1Filed Nov. 17, 1936 Feb. 3, 1942. J. MERCIER 2,271,826v

PLANT FOR PNEUMATIC, HYDRAULIC, 0R LIKE FLUID CONTROL Filed Nov. 17,1956 2 Sheets-Sheet 2 J EM/ 445/705,?

Patented Feb. 3, 1942 amaze PLANT FOB PNEUMATIC, HYDRAULIC, B

LIKE FLUID CONTROL Jean Mercier, Nenilly-sur-Seine, France ApplicationNovember 11, ms, Serial No. 111,223 In France November 27, 1935 Claims.(01. its-4:)

One or more tanks for the storage of the de-' livered fluid, said tankor tanks being provided with a check-valve;

Distributers tor the fluid under pressure supplied by the said storagetanks, and Jacks or like devices supplied with fluid under pressure bythe distributers.

By means of the check-valve, which is located between the outlet of thepump and each of the said storage tanks the pressure prevailing in thetank may be conserved. This pressure may serve to control several timesin succession the jacks or like parts which are to be displaced,notwithstanding a breakage of the pipes on the upstream side of thecheck-valve or a breakdown of the pump or a breakdown of the motor whichdrives the pump.

If necessary, one or more distributers can be connected directly withthe delivery end of the pump, without being fed by said storage tank orAccording to another feature of the invention,

the pump comprises a pipe for the evacuation of air and for re-priming,said pipe connecting the intake end of the pump to the top of thefeeding tank, which latter is in tree connection with the atmosphere.

Instead of using a pipe for evacuation of air, use can be made of asubmerged pump, i. e., a pump located in immediate proximity to theaforesaid tank to which it is connected in this In the case in which thefluid' employed is air, the Jacks may discharge into the atmosphere.

It is also feasible, in the case of air or any other gas, to use anarrangement in closed circuit, and herein the distributing valves arepreferably situated at the lowest points of the circuits. A small amountof oil or other liquid is provided in these circuits and collects atthese lowest points, thus insuring absolutely non-leakin: conditions forthe said valves; the oil which is drawn along with the air or other gaswill again enter the intake pipe of the compressor.

In the accompanying drawings, which are given solely byway of example,

Fig. l isa diagrammatic general view of the improved hydraulic orpneumatic control in accordance with the invention;

Fig. 1a shows a modification;

Fig. 2 is a like view of a modification;

Fig. 3 is a like view, showing a preferred modification of a pneumaticplant.

In the embodiment shown in Fig. 1, the plant comprises a pump I, whichmay be of any type. This pump withdraws the liquid, such as oil or thelike, through a pipe 2, from a feeding tank 3, which is at a higherlevel than the pump. The

top of tank 3 is connected with the atmosphere 1 by a pipe I. This pipe,if necessary, may be provided with any usual check-valve which willprevent all loss of liquid, for instance when the entire plant standsupside down or when the aircraft upon which the said plant is mountedosciilates or is inclined. I

The inlet end of the pump is connected by a pipe 5 to the top of thesaid tank thus insuring the automatic priming of the pump after thewhole system has been turned upside down, since any amount of air thathas been trapped in the pump escapes through pipe 5 and is replaced by acorresponding amount of liquid present in the lower portion 0! said pipe5, connected to the inlet side of the pump. 1

Instead of using the aforesaid arrangement,

the pump may be placed at I (Fig. .la) in imme- .is separated into twochambers 8 and 9 by a piston III, which is guided, for instance, by aguide Ii. Between the-piston l0 and the cylinder 1 are provided one ormore packing pieces I2,

, for instance of the elastic type, and thus there pump when thedelivery pressure attains a given maximum value, by directly connectingthe pipe 8, by means of a pipe Hi, to the pipe l1 serving for thegeneral return of the liquid to the top of the feeding tank 8 (acheck-valve may be provided at II at the point where the pipe I1 opensinto the tank). The bypass may be of any known type, and in theconstruction represented in the figure, it comprises a piston is whichis urged to the right by a spring 28.

The chamber 8 of the storage device 1'is connected by a pipe 28(provided with a pressuregauge 28), and by branch pipes 8I8i'- 8i" todistributers 28-28'28" which control the delivery of compressed'liquidto one or'more Jacks 21-21 21' and 21", respectively. The distributorsalso direct fluid to pipes 28, 28 and 28, while return is permittedthrough 28, 28, and 28* respectively to pipes 28, 28', and 28" leadingto return pipe II, as shown by Fig. 1. Or the fluid may be directed topipes 28 28' and 28' while return is permitted through 28*, 28 and 28,respectively. The jacks 21'-21, 21' 21" serve to actuate any elementwhich is to be moved. For instance, the jacks 21-21 may be used to liftthe landing gear of an aeroplane, the jack 21' may control the bodyflaps, and the jack 21" may operate the cooling radiators 28 which canextend more or less out of the fuselage II.

The operation of the said plant is as follows: The pump withdraws liquidthrough the pipe 2 from the tank 8 and delivers it through the pipe 8into the chamber 8 of the storage device 1. Thisdelivery continues up tothe moment where the maximum pressure is attained. As soon as thismaximum has been reached, the by-pass short-circuits'the pump. Thus thepilot has at any time a reserve supply of compressed liquid contained inthe-said storage device, and hence he may at any time, by operating oneof the distributers 2828'28", act in the desired direction upon any ofthe jacks 21-21, 21', 21", and in this manner upon the parts to bedisplaced.

As above indicated, owing to the check-valve H, the storage device 1will be cut off from the upstream part which is under the pressure ofthe plant, so that a breakage of one of the pipes 2 or 8 will notdeprive the pilot of the reserve supply of compressed liquid, and thuswill be sumcient to provide for all desired operations for a safelanding on ground or on water.

Obviously, the by-pass I! can be replaced by any other suitable device.

Fig. 2 represents a modification in which the delivery pipe 8 of thepump I, forwardly of the by-pass l8, comprises a branch at 88.

A branch pipe 8|" leads directly to a distributer 28" adapted to supplya Jack 21" which may perform any desired operation of any pivotally orslidably mounted elements of the aircraft. The control of the saiddistributer is insured, for instance, by a thermostat 82.

Another branch 88 of the delivery pipe leads to two storage devices1--1' which are disposed in parallel, and are provided with check-valvesH-ll Each of the said storage devices is connected to one or moredistributers 28-28 supplying jacks 2121'-,'21' The first two jacks(21-21") may serve tooperate the disappearing landing gear of anaeroplane, and jack 21' may operate a device of any kind, such as superplaning device, an aerodynamic brake, a body flap, etc. The return offluid to the tank 8 takes place in parallel by the pipes 2828'--28", asin the previous construction.

This arrangement of several storage devices permits of'reducing thelength of the different pipes and of making the various parts of theplant independent. As will be noted, the part 28"21" is not providedwith storage devices, but this part controls the movement of auxiliarydevices, 1. e., it performs an operation which is in fact auxiliary andwhose stopping will not have any serious consequences, at least for themoment.

The aforesaid arrangements can be actuated quite as well by liquids asby air or gas.

In the case of air, the jacks or other apparatus may discharge into theatmosphere or into the inlet pipe of the compressor, and thus thenecessary power can be greatly reduced. This latter method which resultsin the use of a closed circult, will be naturally employed whenever useis made of a gas other than air.

Whether air orother gas be used, it will be advantageous to employpreferably an arrangement analogous to the one shown in Fig. 3.

In this embodiment, the plant comprises a compressor I in two stages.The air or other gas is for instance withdrawn at 88, compressed in acylinder 88 and then driven through the cooling worm 88 into a secondcylinder 81 in which it is again compressed. From this cylinder 81 thecompressed air (or other fluid) is caused to flow into a storage device1 wherefrom a portion thereof through a pipe 88 into a distributer 88;another pipe 88' leads to two storage devices 1' and 1' connected inparallel.

Each of the storage devices 111 is provided at its lowest part, with acorresponding check-valve M-lh-ll".

Preferably the circuit is closed, 1. e., the discharge endof the Jacks,or like devices, supplied by the storage devices, is connected to thesuction pipe 84 of the compressor. Preferably an interinediary tank 88is interposed between 28 and In the case of a closed circuit, thiscircuit will preferably contain a small quantity of oil or other liquid,which will collect at the lower points of the plant, at which points thecheck-valves "-10-" are located, and the said liquid will form tighthydraulic joints in these places. A small quantity of oil or otherliquid will of course be drawn into the jacks. but this will proceedfrom the discharge end of the jacks to the inlet end of the compressor,and will finally arrive at the lowest points, where it can again act inits sealing capacity. I

The compressor is preferably provided with a valve 88 (Fig. 3) of anyknown type for the admission of air. which can be adjusted for anydesired pressure, for instance slightly above the discharge pressure ofthe jack or Jacks.-

Obviously, as in the preceding case, one or more pipes 3|, directlyconnected with the delivery end of the pump, may lead directly to one ormore distributers, without the use of a storage device in this circuit.

It is evident that the said invention is not limited to the embodimentsherein described and represented, which are given solely by way ofexample. 7 i

Having now described my invention, what I claim as new and desire tosecure by Letters Patent, is:

1. In a system for controlling a hydraulically operated device, thecombination of a storage tank for liquid under pressure, resilient meansassociated with said tank for varying the pressure therein in accordancewith the amount of liquid present in said tank, delivery means forsupplying liquid under pressure for replenishing said storage tank,including a circuit adapted to communicate with said storage tank forthe feed of liquid thereto when the pressure in said tank is lowerthanthe pressure of liquid in said feed circuit, means for limiting thepressure of the liquid supplied by said circuit to a given value, meansfor cutting off said storage tank from said feed circuit when thepressure in said delivery means drops below the pressure in said storagetank, and means, wholly independent of said feed circuit, for connectingsaid storage tank with said device to be operated.

4. In a system for controlling a hydraulically operated device, thecombination of a storage tank for liquid under pressure, resilient meansassociated with said tank for varying the pressure therein. inaccordance with the amount of liquid present in said tank, a feedingtank, a pump system connected to said tank including a delivery chamber,a spring relief valve in said chamber 'for discharge of liquidtherefrom, whereby the pressure in said chamber is limited to apredetermined value, a communication between said delivery chamber andsaid storage tank, a check valve mounted in said communi- 2. In a systemfor controlling a hydraulically I operated device, the combination of astorage tank for liquid under pressure, resilient means associated withsaid tank for varying thepressure therein in accordance with the amountof liquid present in said tank, delivery means for constantly holdingliquid under pressure available for replenishing said storage tank,including a circuit adapted to communicate with said storage tank forthe feed of liquid thereto when the pressure in said tank is lower thanthe pressure of liquid in said feed circuit, means for limiting to agiven value the pressure of the liquid in said feed circuit, a checkvalve interposed between said feed circuit and said storage tank adaptedto open in the direction of said storage tank, and conduit means, whollindependent of said feedcircuit, for connecting said storage tank withsaid device to be operated.

3. In a system for controlling a hydraulically operated device, thecombination of a storage tank for liquid under pressure, resilient meanscation adapted to open only in the direction of said storage tank, andconduit means, wholly independent of said feed delivery chamber and saidpump system, for connecting said storage tank with the above mentioneddevice to be operated.

5. In a system for controlling a hydraulically operated device, thecombination of a storage tank for liquid under pressure, resilient meansassociated with said tank for varying the pressure therein in accordancewith the amount of liquid present in saidtank, a feeding tank, a

' pump, a main conduit connecting the inlet of said pump with the bottomof said tank, a supplementary conduit connecting the inlet of said pumpwith the top of said tank, a delivery chamber connected with the outletof said pump, pressure relief means in said chamber for the discharge ofliquid therefrom, whereby the pressure in said chamber is limited to apredetermined value, a communication between said delivery chamber andsaid storage tank, a checkfvalve mounted in said communication adaptedto open only in the direction of said storage tank, and conduit means,wholly independent of said pump chamber and the pump conduits, forconnecting said storage tank with said device to be operated.

JEAN MERCIER.

